‘They should therefore be thinned out and transplanted. This can be easily and speedily done, on a large scale, by dredging from a steamer at the proper time of the year, when the young oysters are at the best age for transplanting. ‘Finally, there is no reason for any despondency in regard to the future of the pearl-oyster fisheries if they are treated scientifically. The adult oysters are plentiful on some of the paars, and seem for the most part healthy and vigorous; while young oysters in their first year, and masses of minute spat just deposited, are very abundant in many places.’ The chief causes of the failure of the fisheries, at any rate the chief causes which can be dealt with by man, are overcrowding and over-fishing. It might be supposed that these factors would counteract each other; but it must be remembered that they become effective at the two opposite poles of the oyster’s existence, which is thought to cover five, six, or seven years. The overcrowding takes place when the oyster is quite young and hardly fixed on the submerged reefs, whilst the over-fishing takes place when the animal is fully matured and perhaps growing old. The fact that Professor Herdman and Mr. Hornell conveyed the young oysters from Manaar in the north of the island by boat to Colombo and then on by train to Galle in the south, and there succeeded in rearing them, shows that there would be little difficulty in artificially rearing oysters in convenient localities and then transplanting them to such fishing-grounds as show danger of depletion. With regard to over-fishing, if the grounds are under the charge of a trained zoologist there is no reason why this should go on.